Evaluation of the effects of granulated alumina powder characteristics and die wall lubricant on compaction behavior using X-ray computed tomography

Segawa, Tomoomi ; Kawaguchi, Koichi  ; Ishii, Katsunori ; Nishina, Masahiro; Makino, Takayoshi ; Iimura, Kenji*; Satone, Hiroshi*; Suzuki, Michitaka*; Natori, Yuri*

Japan Atomic Energy Agency has developed a simplified pelletizing fuel fabrication system. In this system, the flowability of a MOX raw powder is improved by wet granulation for the pelletizing process, and the die wall lubrication method directly presses the granulated MOX powder into green pellets without adding any lubricant into the powder. The homogeneous compression is important to fabricate high-density green pellets. However, it is difficult to observe the compaction behavior in situ. Therefore, the capping phenomenon was investigated by using X-ray computed tomography and alumina powder that is highly transparent against X-rays. When lubricant was used, the breakage of the particles extended to the bottom compared with not used. This result indicates that the die wall lubrication is effective for the homogeneous compression of granulated powders.